The invention relates to a device for winding a roving onto bobbin tubes using a turret winding head.
With roving machines, so-called rovings or slivers are produced, which are used as feed for spinning a fiber yarn, for example, on a ring spinning machine. The roving serving as feed for ring spinning machines is usually produced from a drafter sliver that is drafted on a drafting arrangement of the roving machine and is subsequently provided with a slight twist so that the roving can be wound onto a bobbin in a draft-free manner. The imparted twist must only be to such an extent that the coherence of the fibers is strong enough for winding and unwinding again and transport of the bobbins. On the other hand, with regard to the draft on the ring spinning machines, this so-called producer twist has to be so little that in the further production process, no drafting faults occur. The roving has to be draftable despite the applied producer twist.
For producing the roving, so-called flyers are used as a roving machine. The flyer is typically equipped with a drafting arrangement and a spindle for winding the roving onto a flyer tube by means of a flyer. For process-related reasons, the flyer tubes or, respectively, the spindles for receiving the flyer tubes are aligned vertically. Imparting the producer twist via the flyer and unwinding the roving takes place in one process step in which the spindle rotates with the flyer tube located thereon, and the flyer guiding the sliver to the flyer tube rotates around the flyer tube. Nowadays, the finished bobbins are removed from the roving machine by means of automatic doffers and are delivered in automatic displacement systems out of the flyer and are fed to the ring spinning machines for further processing.
However, in the meantime, forms of roving machines other than the conventional flyers have become known, which have in common that a producer twist is imparted to the roving in a twisting means downstream of the drafting arrangement. The roving with the producer twist is subsequently fed to a winding device. Imparting the producer twist and winding the roving is carried out in two process steps, which are independent of each other. Accordingly, in such roving machines, winding devices can be used other than is the case in a flyer.
Such a winding device is disclosed in EP 2 112 258. The construction of the disclosed winding device takes account of the high delivery speeds of the roving machine. However, the winding device according to EP 2 112 258 has the disadvantage that for replacing a full bobbin with an empty tube, the winding process and therefore the delivery of the roving from the twisting means has to be interrupted. Depending on the embodiment of the twisting means, piecing after an interruption means loss in productivity and quality.
When using conventional flyer tubes in a roving machine according to EP 2 112 258, due to the high delivery rates of 600 m/min and higher, very frequent tube changes are necessary. Therefore, a winding device according to EP 2 112 258 is not suited for the use of flyer tubes. Flyer tubes according to the prior art are disclosed, for example, in EP 0 927 696. A flyer tube is a tube having an outer casing surface and an inner casing surface. The outer casing surface serves for winding thereon roving from a fiber material and has a region with a starter strip or another device for receiving the roving end at the beginning of the winding after a bobbin change. The inner casing surface is formed such that it is suitable in terms of size and shape to be received by transport means known from the prior art for transporting full or empty tubes, or to be received in devices for further processing the roving.
From the production of chemical fibers, winding machines are known that are suitable for continuously fed threads. Such a winding machine is disclosed, for example, in EP 1 053 967. The winding machine has a turret winding head on which two bobbin chucks are held. A first bobbin chuck is in a winding position and a second bobbin chuck is in a doffer position. In the doffer position, the full bobbins are removed from the bobbin chuck and replaced by an empty tube. If the bobbins in the winding position are full, the turret is rotated by 180° and the bobbin chucks change position. The incoming threads are separated from the full bobbins without the delivery being interrupted by the performed rotation, and are taken over by the empty tubes. The bobbin chucks are arranged horizontally. Moreover, due to the traversing mechanism, the threads are not wound in a draft-free manner. The thread guide, from which the thread changes to the traversing mechanism, is spaced at a certain distance from the traversing mechanism itself. Through this, the path for the thread from the thread guide to the outermost position of the traversing mechanism is longer than it is when the traversing mechanism is in the middle position. Because of this, each movement of the traversing mechanism results in a certain draft.